window.onload = function () {
    var minSize = 15; //最小字体
    var maxSize = 30;//最大字体
    var newOne = 600; //生成雪花间隔
    var flakColor = "#1bd3ff"; //雪花颜色
    var flak = $("<div></div>").css({position: "absolute", "top": "0px"}).html("❉");//定义一个雪花
    var dhight = $(window).height(); //定义视图高度
    var dw = $(window).width() - 80; //定义视图宽度
    setInterval(function () {
        var sizeflak = minSize + Math.random() * maxSize; //产生大小不等的雪花
        var startLeft = Math.random() * dw; //雪花生成是随机的left值
        var startOpacity = 0.7 + Math.random() * 0.3; //随机透明度
        var endTop = dhight - 100; //雪花停止top的位置
        var endLeft = Math.random() * dw; //雪花停止的left位置
        var durationfull = 5000 + Math.random() * 3000; //雪花飘落速度不同
        flak.clone().appendTo($("body")).css({
            "left": startLeft,
            "opacity": startOpacity,
            "font-size": sizeflak,
            "color": flakColor
        }).animate({
            "top": endTop,
            "left": endLeft,
            "apacity": 0.1
        }, durationfull, function () {
            $(this).remove()
        });
    }, newOne);
}